JP3075125B2 - Control device for automatic transmission for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic transmission for a vehicle, and more particularly to a device for controlling an engagement hydraulic pressure of a friction engagement device when shifting to a travel range in which an engine brake is effective.

[0002]

2. Description of the Related Art An automatic transmission for a vehicle is configured to set a low speed gear by engaging a one-way clutch in order to reduce shift shock or facilitate shift control. I have. On the other hand, the effect of the engine brake is more effective at a lower gear. Therefore, when setting a predetermined low gear, it is necessary to be able to select two states, a state in which the engine brake works and a state in which the engine brake does not work. By switching the manual valve, the travel range is switched, and thereby a non-directional friction engagement device such as a multiple disc brake arranged in parallel with the one-way clutch is engaged.

[0003] By the way, a driving range in which engine braking does not work (hereinafter, temporarily referred to as non-engine braking range).
If the vehicle shifts to a driving range where the engine brake works (hereinafter, tentatively referred to as the engine brake range), a downshift occurs at a vehicle speed at which engine overrun does not occur, and friction engagement is applied to apply the engine brake. The device engages. In this case, since a large torque acts on the friction engagement device that is engaged to set the shift speed, the engagement hydraulic pressure should be increased in order to prevent excessive slippage and shift shock of the friction engagement device. Has been done in the past. Japanese Patent Application Laid-Open No. Sho 62-13850 discloses a device provided with a delay means for delaying boost control in order to prevent a downshift with a high line pressure when shifting from a non-engine brake range to an engine brake range. Is described.

[0004]

Normally, the braking of a running vehicle is performed by the driver depressing a foot brake, for example, and finely adjusting the depressing force to control the deceleration. However, when the downshift is performed by the above-described shift operation in conjunction with the brake operation by the driver, the inertia phase during the shift transition (from the rotational speed at the high-speed gear stage to the rotational speed at the low-speed gear stage). During which the rotational speed is changing), a relatively large negative torque may be generated. In this case, since the deceleration due to the negative torque is superimposed on the deceleration due to the brake operation, the driver experiences a deceleration greater than the deceleration due to the brake operation. The driver is given a feeling of deceleration, which may cause a deterioration in driving feeling.

The present invention has been made in view of the above circumstances, and has as its object to provide a control device capable of preventing an excessive feeling of deceleration during a manual downshift.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention is to reduce the engagement oil pressure of a friction engagement device which is engaged during a manual downshift to a gear position where engine braking is effective. It is characterized in that it is provided with means for controlling so that it is different between when the brake is operated and when the brake is not operated. More specifically, as shown in FIG. 1, a manual shift device 1 that manually switches between a traveling range in which engine braking is not effective at a predetermined gear and a traveling range in which engine braking is effective at that gear; An automatic transmission for a vehicle, comprising: a friction engagement device 2 that is engaged to set the gear position in a travel range in which a brake is effective; and a hydraulic adjustment device 3 that controls an engagement oil pressure of the friction engagement device 2. A control device, comprising: a shift detecting means for detecting that a shift has been made from a travel range in which the engine brake does not work to a travel range in which the engine brake works, and a braking detecting means for detecting that a brake operation is being performed. 5, when the driving range is shifted from the running range where the engine brake does not work to the running range where the engine brake works, Instruction means 6 for outputting an instruction signal to the hydraulic pressure adjusting device 3 so that the engagement hydraulic pressure to be engaged is lower when the brake is operated than when the brake is not operated. It is.

[0007]

In the automatic transmission according to the present invention, by operating the manual shift device 1, it is possible to shift from the travel range where the engine brake does not work to the travel range where the engine brake works. The hydraulic pressure of the frictional engagement device 2 that is engaged in the travel range in which the engine brake works is controlled by the hydraulic pressure adjustment device 3.

When the manual shift device 1 shifts from the travel range where the engine brake does not work to the travel range where the engine brake works, the shift detecting means 4 detects this, and at that time, the braking detecting means 5
Detects whether the brake is operated. When it is detected that the vehicle is shifted to the travel range in which the engine brake is effective in the state where the brake is operated, the engagement hydraulic pressure of the friction engagement device 2 is set to be lower than when the brake is not operated. Then, the instruction means 6 outputs an instruction signal to the hydraulic pressure adjustment means 3. Therefore, the braking effect due to the engagement of the friction engagement device 2 in the traveling range in which the engine brake is effective is reduced when the brake is operated, and fine adjustment of the deceleration is performed by the brake operation. Deterioration of driving feeling can be prevented.

[0009]

Next, the present invention will be described in detail based on embodiments. FIG. 2 is a block diagram schematically showing an embodiment of the present invention. In the automatic transmission 10 shown here, a predetermined frictional engagement device is engaged and released by a hydraulic control circuit 11, It is configured such that four forward speeds and one reverse speed can be set. Fig. 3 shows an example of the gear train.
The torque converter 1 will be described below.
After the second gear, a third-speed transmission unit 13 is provided, and an output-side overdrive unit (O / D unit) 14 of the third-speed transmission unit 13 is provided.

The three-speed transmission unit 13 is mainly composed of two sets of single pinion type planetary gear mechanisms 15 and 16, and the sun gears 17 and 16 of these planetary gear mechanisms 15 and 16.
18 are connected so as to rotate integrally, and the carrier 19 of the first planetary gear mechanism 15 is
Is connected to the ring gear 20 of the planetary gear mechanism 16. Further, the ring gear 21 of the first planetary gear mechanism 15
A first clutch C1 for selectively connecting the input shaft 23 and the input shaft 23 connected to the turbine runner 22 of the torque converter 12 is provided. Further, between the input shaft 23 and the sun gear 17 of the first planetary gear mechanism 15, there is provided a second clutch C2 for selectively connecting the two.

As brake means, there are provided a first brake B1 for selectively stopping the rotation of the sun gear 17 of the first planetary gear mechanism 15, a first one-way clutch F1 and a second brake B2. That is, the first brake B
Reference numeral 1 denotes a so-called first speed coast brake, which is constituted by a band brake disposed on the outer peripheral side of the clutch drum of the second clutch C2 integrated with the sun gear 17. The one-way clutch F1 and the second brake B2, which is a multi-plate brake, are arranged in series between the sun gear 17 and a predetermined fixed portion 24 such as a casing.

The braking means for the second planetary gear mechanism 16 will be described.
4, a second one-way clutch F2 is disposed. In parallel with the one-way clutch F2, a third brake B3 which is a multi-disc brake as a so-called second speed coast brake is disposed.

The O / D unit 14 includes a set of planetary gear mechanisms 26.
The carrier 27 is connected to the ring gear 20 of the second planetary gear mechanism 16, which is the output member of the third-speed transmission unit 13. Between the carrier 27 and the sun gear 28, a one-way clutch F0 and a multi-disc brake C0 for selectively connecting and integrating the two are selectively provided.
Are provided in a mutually parallel relationship. Further, a multi-plate brake B0 for selectively fixing the sun gear 28
Are provided between a predetermined fixing portion 24 and the fixing portion 24. The ring gear 29 is connected to the counter drive gear 30.

In FIG. 3, reference numeral 31 denotes a counter driven gear, 32 denotes a counter shaft, and 33 denotes a differential gear.

By having the gear train described above,
Four forward speeds and one reverse speed including the overdrive speed can be set. FIG. 4 shows the engaged / disengaged state of each friction engagement device for setting each of these shift speeds. In FIG. 4, a circle indicates an engaged state, and a blank indicates a released state.

The automatic transmission 10 shown in FIG. 2 is adapted to engage / disengage each friction engagement device by a hydraulic control circuit 11, and furthermore, an electronic control unit for controlling the hydraulic control circuit 11. (ECU) 34 is provided.
The ECU 34 is mainly composed of a central processing unit (CPU), a storage device (RAM, ROM) and an input / output interface. The ECU 34 shifts a solenoid valve or a linear solenoid valve (shown in FIG. Instead, an electric signal is output to perform shift control, lock-up clutch control, or hydraulic control during shift transition. The ECU 34 stores the control data in the hydraulic control device 11 as control data.
, A signal from a shift device 35 for switching a manual shift valve, a signal from a brake switch 36 that is turned ON by depressing a brake pedal (not shown), or various types of sensors such as a vehicle speed sensor, a brake oil pressure sensor, and a brake stroke sensor. Signals from the sensors 37 are input. Further, in order to detect the operation state of the automatic transmission 10, a signal from a rotation speed sensor 38 for detecting the rotation speed of a predetermined rotating member such as the turbine runner 22 is input to the ECU 34.

The above-described hydraulic control circuit 11 can control the coast brake pressure at the time of shift transition to a high level and a low level will be described with reference to FIG. The example shown in FIG. 5 is an example in which the hydraulic pressure of the first brake B1, which is the second speed coast brake, is controlled, and the manual valve 40 controlled by the shift device 35 to switch is conventionally known. In the same manner as in the case where the shift unit 35 is selected, the position can be set to six positions of P, R, N, D, S, and L according to each range that can be selected by the shift device 35. , L, the line hydraulic pressure PL according to the reverse (R), drive (D), second (S), and low (L) ranges.
Is output. From the D port,
The line oil pressure PL is output when any of the D range, S range, and L range is set, and the line oil pressure PL is output from the S port when the S range or L range is set. When the L range is set, the line hydraulic pressure PL is output.

The 1-2 shift valve 41 switches between the first speed and the second speed. The input port 42 is connected to the D port of the manual valve 40. this
A second solenoid valve SOL2 is connected to the control port 43 of the 1-2 shift valve 41. When the solenoid valve SOL2 outputs a signal pressure, the 1-2 shift valve 41 performs a switching operation, and When the input port 42 is closed and the signal pressure from the solenoid valve SOL2 is not applied to the control port 43, the input port 42 is connected to the output port 44.

Output port 4 of this 1-2 shift valve 41
The output port 44 is connected to an input port 46 of a second shift valve 45, while the second brake B2 is connected to the second brake B2. The control port 47 of the second shift valve 45 communicates with the S port of the manual valve 40. When a signal pressure is applied from the S port, that is, the switching operation is performed in the S range or the L range, and the input port 46 is output. Port 48
It is constituted so that it may be connected to.

The 2-3 shift valve 50 is a valve for executing a shift between the second speed and the third speed by receiving a signal pressure from the first solenoid valve SOL1 and performing a switching operation. Are connected to the D port of the manual valve 40. The second input port 52 is connected to the output port 4 of the second shift valve 45.
8 is communicated. The communication between the input ports 51 and 52 and the output ports is, as indicated by the symbol in FIG.
, And communicates with the lower port at the third speed and the fourth speed. That is, the first
When no signal pressure is applied from the solenoid valve SOL1, each of the input ports 51 and 52 communicates with a port on the upper side in FIG. 5 so that the first input port 51 is connected to the first output port 53 from the first output port 53. A signal pressure is output to a 3-4 shift valve (not shown), and a second input port 52
Communicates with the second output port 54, and outputs hydraulic pressure to the first brake B1 therefrom. On the contrary, when the signal pressure is supplied from the first solenoid valve SOL1, the first input port 51 communicates with the third output port 55, from which the above-mentioned 1-2 shift valve 41 The signal pressure is output to the hold port 41h, and the input port 42 is held in a state where the input port 42 communicates with the output port 44. At the same time, the second input port 52 is shut off.

The second output port 54 of the 2-3 shift valve 50 is connected to a second coast modulator valve 61 via a B1 orifice control valve 60 controlled by the hydraulic pressure of a second brake B2. This second coast modulator valve 61
Is a valve for supplying an output pressure to the feedback port 62 and applying a signal pressure to oppose the output pressure to regulate the engagement pressure of the first brake B1. The signal pressure port 63 has an accumulator control valve 7
0 output port 71 is connected. The accumulator control valve 70 regulates and outputs the line pressure PL based on the throttle pressure Pth and the signal pressure of the linear solenoid valve SLN.
The output pressure increases as th increases, and the output pressure decreases as the output signal pressure of the linear solenoid valve SLN increases.

Therefore, in the second coast modulator valve 61, the higher the throttle pressure Pth, the higher the pressure adjustment level and the engagement hydraulic pressure of the first brake B1 changes at a high pressure, which is output from the linear solenoid valve SLN. The higher the signal pressure, the lower the pressure adjustment level and the engagement hydraulic pressure of the first brake B1 changes at a lower pressure.

The first brake B1 is shifted from the third speed to the second speed by, for example, shifting from the D range where the engine brake does not work at the second speed to the S range where the engine brake works at the second speed. It is engaged when shifting. The engagement hydraulic pressure of the first brake B1 is controlled differently between when the brake is operated and when the brake is not operated during the so-called manual downshift.

That is, when the shift to the second speed occurs by switching to the S range while the vehicle is traveling at the third speed in the D range, in the hydraulic circuit shown in FIG. 5, the line pressure PL from the S port of the manual valve 40 is increased. Is output, and thus the second shift valve 45 is switched. Since the line pressure PL is supplied to the input port 46 of the second shift valve 45 from the output port 44 of the 1-2 shift valve 42, the output of the output port 48 is The line pressure PL is sent to the second input port 52 of the -3 shift valve 50. The 2-3 shift valve 50 switches so that the second input port 52 communicates with the second output port 54 when the second speed in the S range is determined, so that the B1 orifice The second coast modulator valve 6 via the control valve 60
1 is supplied with the line pressure PL. Then, the adjusted hydraulic pressure is supplied to the first brake B1, which is a second coast brake, and this brake B1 is engaged.

FIG. 6 is a flowchart showing an example of a routine for controlling the engagement hydraulic pressure of the first brake B1.
First, in step 1, the shift device 35 is operated to determine whether a downshift from the third speed in the D range to the second speed in the S range (so-called manual downshift: MNL down) has occurred. If the determination result is "yes", it is determined whether or not the brake is on (step 2). The determination in step 2 is based on the brake switch 36 described above.
Can be determined based on whether or not the switch has been turned on.

If the brake switch 36 is OFF because the brake pedal is not depressed, the coast brake servo pressure for engaging the first brake B1 is set to P
Zero pressure is output (step 3). The P0 pressure is a predetermined constant pressure or a hydraulic pressure determined according to the vehicle speed, etc., and by controlling the duty ratio of the linear solenoid valve SLN to change its output signal pressure, the second coast modulator valve 61 is controlled. Is set by changing the pressure regulation level of

On the other hand, if the brake pedal is depressed and the brake switch 36 is ON, the coast brake servo pressure P1 corresponding to the deceleration α is calculated (step 4).
The coast brake servo pressure P1 corresponding to the deceleration α is output (step 5). The deceleration α may be a value directly obtained by a deceleration sensor or the like, or a value calculated from an output signal pressure from a vehicle speed sensor, an output signal from a brake pressure sensor, an output signal from a brake stroke sensor, or the like. It may be. The coast brake servo pressure P based on the deceleration thus obtained is
1 is a pressure lower than the aforementioned P0 pressure. The levels of these hydraulic pressures are schematically shown in FIG.

The control of the P1 pressure can be performed by, for example, changing the output signal pressure from the linear solenoid valve SLN to a high level or a low level. More specifically, the control can be performed by controlling the duty ratio. By increasing the output signal pressure (SLN pressure) of the linear solenoid valve SLN as the speed α increases, the output pressure of the accumulator control valve 70 decreases, so that the pressure regulation level of the second coast modulator valve 61 decreases.
The engagement hydraulic pressure (B1 pressure) of the first brake B1 decreases. This relationship is schematically shown in FIG.

As described above, when a downshift is caused by shifting from the running range where the engine brake does not work to the running range where the engine brake works, a relatively large negative torque may appear in the inertia phase during the shift transition. However, when the brake operation is performed as described above, the engagement hydraulic pressure of the first brake B1 for executing the manual downshift is set to a lower pressure than when the brake operation is not performed. The deceleration does not appear to overlap with the deceleration due to the negative torque, or the negative torque is reduced, so that the occurrence of excessive deceleration is prevented. That is, even if the manual shift down is performed with the brake operation,
The deceleration according to the brake operation can be obtained, and therefore, an excessive braking feeling can be prevented, and the driving feeling can be maintained in a good state. In particular, if the coast brake servo pressure is controlled according to the deceleration α as shown in FIG. 6, it is possible to more effectively prevent the driving feeling from deteriorating.

In the above-described embodiment, the case where the downshift from the third speed to the second speed occurs with the shift from the D range to the S range has been described as an example.
The present invention is not limited to the above embodiments,
Similar control can be performed when a downshift to the first speed is caused by shifting from the D range to the L range. In this case, by controlling the pressure adjustment level of the low coast modulator valve by the output pressure of the accumulator control valve, the engagement hydraulic pressure of the third brake, which is a low coast brake, is turned on / off of the brake.
The level may be controlled to be high or low according to the F state. Further, in the present invention, the coast brake servo pressure may not be controlled in accordance with the output pressure of the accumulator control valve, but may be directly controlled by a linear solenoid valve or the like. Further, in the above-described embodiment, an example in which the present invention is applied to the control device for the automatic transmission having the gear train shown in FIG. 3 has been described. However, the present invention is applicable to a gear train other than the gear train shown in FIG. The present invention can be applied to a control device for an automatic transmission including The same applies to the hydraulic circuit, and the present invention can be applied to a control device having a hydraulic circuit other than the hydraulic control circuit shown in FIG.

[0031]

As explained above, according to the present invention,
When a downshift occurs due to a shift to the travel range where the engine brake works, if the brake is operated, the engagement hydraulic pressure of the friction engagement device that executes the downshift is set lower than when the brake is not operated. Because the motor is configured to be set lower, the negative torque that appears during the inertia phase of the downshift can be suppressed. As a result, even if the deceleration due to the negative torque overlaps the deceleration due to the brake operation, excessive deceleration is prevented. Therefore, the driving feeling during a manual downshift can be maintained in a good state.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing the present invention by functional means.

FIG. 2 is a block diagram schematically showing one embodiment of the present invention.

FIG. 3 is a skeleton diagram showing the gear train.

FIG. 4 is a chart showing an engagement operation table for setting each shift speed.

FIG. 5 is a hydraulic circuit diagram schematically showing a main part of the hydraulic control circuit.

FIG. 6 is a flowchart illustrating an example of a routine for controlling a coast bouquet servo pressure in accordance with an operation state of a brake.

FIG. 7 is a time chart schematically showing a change in coast brake servo pressure.

FIG. 8 is a diagram showing a relationship between an output signal pressure of a linear solenoid valve and an engagement hydraulic pressure of a first brake.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Manual shift device 2 Friction engagement device 3 Hydraulic pressure adjusting device 4 Shift detection means 5 Breaking detection means 6 Instruction means A Automatic transmission

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-140563 (JP, A) JP-A-62-13850 (JP, A) JP-A-62-204042 (JP, A) 98255 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16H 61/00-61/12

Claims (1)

(57) [Claims] 1. A manual shift device for manually switching between a travel range in which engine braking does not work at a predetermined shift speed and a travel range in which engine braking works at that speed, and the shift speed in a running range in which the engine brake works. A friction engagement device that engages to set
A control device for an automatic transmission for a vehicle, the control device including a hydraulic pressure adjusting device for controlling an engagement hydraulic pressure of the friction engagement device, wherein the driving range is shifted from a driving range in which the engine brake does not work to a driving range in which the engine brake works. Shift detecting means for detecting, braking detecting means for detecting that a brake is being operated, and engaging the friction engagement device when shifting from a running range in which engine braking does not work to a running range in which engine braking works. Instruction means for outputting an instruction signal to the hydraulic pressure adjusting device so that the engagement oil pressure is lower when the brake is operated than when the brake is not operated. Control device.